Principles Of Infectious Disease Epidemiology - Afrohun
PRINCIPLES OF INFECTIOUS DISEASE EPIDEMIOLOGYMODULE I – INTRODUCTION TO EPIDEMIOLOGYThis outline is provided as an aid to the student. It contains only the basic content ofthe module. To view the supporting material such as graphics, examples, etc. pleasesee the module itself.I.INTRODUCTIONA. What is the Purpose of Epidemiology: to better understand the burden and causes of health problems in humanpopulations, and to make changes that decrease risk and improve health.B. Epidemiology is comprised of a set of tools, including: Scientific methods for study/research Techniques for collecting and organizing information Information about the biological basis of health and illness Information about human behavior that affects health “People skills” needed to gain cooperation and gather solid informationC. Epidemiology can be applied to any aspect of human health, including: all types of diseases impairments disabilities injuries the utilization and outcomes of health services, and even good health.D. Epidemiology has been used to study these conditions and many more: West Nile Virus infections Sexually transmitted diseases and HIV Surgical wound infections Hip fractures Childhood malnutrition Pertussis (whooping cough) SchizophreniaE. Epidemiology can help us identify and understand the factors that influencethe emergence, severity, and consequences of health problems. Examplesinclude: tobacco use and lung cancer physical activity and heart disease diet and longevity lead exposure and developmental disabilities1
seat belt use and motor vehicle injuries/deathschildhood vaccine initiatives and child mortalitystatin drugs and outcomes of atherosclerotic heart diseaseThis course will concentrate on the use of epidemiology to understand, preventand control infectious diseases.F. Infectious diseases: Are caused by micro-organisms Are transmitted to humans from other humans, animals or the environment Usually follow recognizable patterns of symptoms, timing, etc. Evolve over time as new organisms emerge and human behavior andenvironments changeG. This module is designed to prepare public health workers to meet thefollowing objectives:1.Define key epidemiologic terms2.Describe at least five factors that significantly influence the incidence anddistribution of a disease in a human population3.Describe the modern approach to epidemiologyII. KEY EPIDEMIOLOGICAL TERMSA. EPIDEMIOLOGY is derived from three Greek root words:epi – on, upondemos – peoplelogy – studyEpidemiology is, thus, the study of what is upon the people. In modern terms, it is thescience of the distribution of disease and its determinants (causes).Epidemiology is also a process that uses the facts at hand as clues to point to newknowledge and solutions. Epidemiologists have been called “disease detectives” and“medical sleuths” for this reason.B. Three key terms are used to describe basic patterns of infectious diseaseoccurrence. The terms are defined by the American Public Health Association (APHA)as:Endemic: The habitual presence of a disease within a given geographic area; may alsorefer to the usual prevalence of a given disease within such an area.Epidemic: The occurrence in a community or region of a group of illnesses of similarnature, clearly in excess of normal expectancy, and derived from a common or from apropagated source.Pandemic: A worldwide epidemic.2
Endemic disease levels are measured by ongoing surveillance systems. Somefluctuations usually occur.The transition from endemic to epidemic can happen in days, weeks, months, oreven years, depending on the disease. It may be hard to tell when the shift begins.There are parallel terms referring to disease patterns in animals that may affecthumans:Zoonosis: An infection or an infectious disease transmissible under natural conditionsbetween vertebrate animals and man (APHA).Enzootic: “Endemic” among animal populationsEpizootic: “Epidemic” among animal populationsC. The term epidemiology is used to refer both to:A method of study of diseases, andA body of knowledge about the natural history of a diseaseThe natural history of a disease is a description of how that disease “behaves” and whatfactors affect its incidence and distribution. Here is a partial list of such calExample:“The Epidemiology of Measles” includes:FactorExampleCausative organismMeasles virusHostHumansMode of transmissionAirborne droplets and direct contact with secretionsIncubation periodAbout 10 days, range 7-18 days from exposurePeriod ofFrom a few days before onset of illness to 4 days after thecommunicabilityappearance of the rashUsual symptomsFever, conjunctivitis, coryza, cough and blotchy red rashComplicationsOtitis media, pneumonia, croup, diarrhea and encephalitisMortality rate2-3 per 1,000 cases in USA; 3-5% in developing countriesEpidemiologic methods were used to compile most of this information.3
III. EVOLUTION OF EPIDEMIOLOGYHuman beings have always sought to understand and explain the occurrence ofdisease and death.A. Supernatural Causation Throughout most of human history, people believed in the supernatural as the causeof illness. Individuals and communities who became ill were thought to have angered the godsor spirits, or to be victims of their enemies’ magic. Such beliefs are still held today, even in otherwise modern societies.B. Environmental Explanations Hippocrates was the first to suggest that disease is caused by environmentalelements, around 400 B.C.E. From 400 B.C.E. until the mid-19th century, many theories were developed to explaininfection. Most of these theories were based on the concept of miasmas. Contagious matterwas thought to create a gaseous form, a miasma, which spread infection through theatmosphere.C. Host Factors Edward Jenner, in 1796, introduced the idea of host resistance to explain why somepeople were immune to smallpox. Peter Panum, in 1846, took this idea further when he studied measles in the FaroeIslands. The islanders had not been exposed to measles in 70 years, and manyotherwise healthy adults died. By contrast, in mainland Denmark all were exposed to measles in childhood, andadult deaths from this disease were rare.D. Toward a Modern ApproachI.John Snow, a British scientist, made the greatest strides toward modernepidemiology in the 19th Century. At that time, infectious diseases were the leading causes of death. Up to half of all children died before the age of five, mostly due toinfectious diseases.a. Snow’s first study was conducted in 1848 when an epidemic of cholera hitthe Golden Square area of London. Even before bacteria were discovered as a cause of disease, Snowwas able to stop devastating outbreaks by observing and recordinginformation about the distribution of the disease. Snow was working from a theory that water had something to do withthe spread of cholera. In the Golden Square area, most people got their water from publicpumps.4
Snow’s first step was to gather information about the cholera patientsin the area, and record their residence or place of work. He developed a spot map that showed the distribution of cases inrelation to the water pumps. Snow investigated all the pumps in the area. One pump was so grossly contaminated that people hadavoided its use. One pump was in an out-of-the way location, and therefore notused much. Many of the cholera cases were clustered around the BroadStreet Pump. When Snow checked with the families of the cholera victims, heconfirmed that they all used the Broad Street Pump.Snow showed that by studying the distribution of cases, a source ofinfection could be found that explained the pattern. He then tookaction to stop the epidemic, by having the pump handle removed.b. Snow did more pioneering work during another cholera outbreak in 1854. This outbreak affected several areas of London that depended onwater hauled in by wagon. Two companies, the Southwark and Vauxhall (S&V) Company andthe Lambeth Company, did the hauling. Some districts were served mostly by S&V, other districts mostly byLambeth, and some districts were served by both. Snow compared the number of cholera deaths in the various districts. Snow realized that the raw numbers of deaths could not tell himmuch. If some districts had many more people than others, they couldn’treally be compared. So he collected population figures from the most recent census andcalculated cholera death rates per 1,000 people. The rates paint a very clear picture. The death rate was 22 times higher in the districts served only byS&V, compared with those served only by Lambeth. Further investigation showed that both companies were drawing theirwater from the Thames River. However, S&V pulled water from a point just downstream from amajor sewer outlet, while Lambeth drew theirs upstream from theoutlet. Snow had shown conclusively that water could serve as a vehicle fortransmitting infection. He also showed that humans could intervene, inthis case by changing the location of the S&V water intake.2. William Farr, the father of modern vital records, was another important figurein the development of epidemiology. His contributions include:5
establishing the first registry of births and deaths in the 1830s. advancing population-based surveillance. distributing reports that led to public health interventions.Example: Mortality in Liverpool, 1843. The median age of survival in Liverpool in 1843was 6 years, compared with an average of 45 in the rest of England. This revelation ledto policy and law changes to improve sanitation.3. Establishment of the Germ Theory (1860 to 1890) Studies by Louis Pasteur and Robert Koch firmly established the germ theory. Attention and research efforts shiftedo to biological agents, ando away from the environment or host resistance. This shift happened in spite of Pasteur’s warning that the role of the environmentwas more important than that of the agent. Snow’s work was not appreciated or expanded upon until the years after WorldWar II.4. Modern Epidemiologya. The modern approach in describing an infectious disease focuses on: the interaction of the disease agent, the host, and the environment.b. The disease agent, the host, and the environment interact dynamically to producedisease. All three of these are constantly changing: Disease agent: Microorganisms adapt to changing conditions, includinghuman control efforts such as antibiotics. Host: Human populations are constantly growing and moving as peopleage, travel, and migrate into new environments. Environment: Changes occur locally and globally, both naturally andthrough human intervention.(i) Disease Agents: There are many “agents” of disease and disabilities,including: nutritional components such as vitamin deficiency diseases and obesity. physical forces such as fire, radiation, and chemicals. biological agents such as bacteria and viruses.In this course, however, we will be focusing on biological agents that will becovered more fully in other segments of the course.(ii) Host Factors: Some host factors that influence susceptibility to disease are:SexRaceAgeOccupation6
NutritionHeredityMarital statusSocioeconomic statusReligious and social customsImmunization historyPrevious history of disease(iii) Environmental Factors: Many aspects of the environment influence both anagent’s survival and growth, and a host’s contact with a disease agent. Some of theenvironmental factors are shown lutionHousing conditionsFood/milkEach disease is influenced by a particular set of factors.Examples:1) Some foodborne diseases, such as salmonella, are highly dependent onenvironmental factors such as cross-contamination and cooking/holding temperatures.2) The spread of measles is influenced by immunization status, but also by housingconditions and nutritional status.3) Disease history is a big factor with some diseases, such as hepatitis A, that conferlifetime immunity after infection.4) Many other diseases can cause repeated infections in the same individual, forexample gonorrhea, shigellosis and malaria.5) Some diseases are transmitted to humans only through arthropod vectors such asmosquitoes, ticks or lice. These disease organisms may have complex lifecycles that pass throughseveral different hosts. For example, the spirochete that causes Lyme Disease is transmitted tohumans from certain ticks, but its lifecycle includes rodents and largemammals such as deer. Vectors are subject to agent, host and environmental factors too.Epidemiology gives us tools to learn about how these factors interact to produce aparticular disease in a particular population. Good epidemiology is most critical wheninvestigating an outbreak or the emergence of a new disease - some of the mostimportant tasks of the field epidemiologist.7
A team approach is almost always used in epidemiologic investigations. The range ofexperts needed depends on the disease and the setting, but usually includes: Epidemiologists Medical professionals (physicians, nurses) Laboratory scientists Statisticians Environmental specialistsSummaryEpidemiology is a set of tools for understanding the burden and causes of healthproblems in human populations, so that we can make changes that decrease risk andimprove health.Epidemiology can help us identify and understand the factors that influence theemergence, severity, and consequences of health problems.Epidemiology is defined as the science of the distribution of disease and itsdeterminants (causes).Human beings have always sought to understand and explain the occurrence ofdisease and death. The modern approach to epidemiology has developed within thepast 150 years.The modern epidemiological approach to infectious diseases focuses on the interactionof the disease agent, the host and the environment.8
PRINCIPLES OF INFECTIOUS DISEASE EPIDEMIOLOGYMODULE II – THE INFECTIOUS DISEASE PROCESSThis outline is provided as an aid to the student. It contains only the basic content ofthe module. To view the supporting material such as graphics, examples, etc. pleasesee the module itself.I. INTRODUCTIONModule II is designed to prepare public health workers to meet the following objectives:1.Describe the six major components of the infectious disease process2.Demonstrate understanding of the concepts of the infectious diseasespectrumII. THE CHAIN OF INFECTIONIn order for infection and disease to occur in an individual, a process involving sixrelated components must occur. This process has been referred to as the “Chain ofInfection.” The six steps or “links” in the chain are: Etiologic agent Reservoir Portal of Exit Mode of Transmission Portal of Entry Susceptible HostIn this module, we will examine each of these links and some other important conceptsthat help us understand infectious disease transmission. To stop the spread of disease,one or more of these links must be broken.A. Etiologic AgentsThere are seven categories of biological agents that can cause infectious diseases.Each has its own particular characteristics. The types of agents ia6.Viruses7.Prions1. Metazoa are multicellular animals, many of which are parasites. Among thediseases they cause are:1
a. Trichinellosis, also called trichinosis, caused by an intestinal roundwormtransmitted through undercooked meat.b. Hookworm, transmitted through feces-contaminated water and soil. Infestationcan cause chronic anemia that often results in retarded mental and physicaldevelopment of children.c. Schistosomiasis, caused by a blood fluke and transmitted throughcontaminated water. Symptoms are related to the number and location ofeggs in the human body, and may involve the liver, intestines, spleen, urinarytract, and reproductive system.2. Protozoa are single-cell organisms with a well-defined nucleus. Some of these arehuman parasites. Examples of diseases cause by protozoa include:a. Malaria, a mosquito-borne disease that is one of the top three infectiousdiseases in the world (along with tuberculosis and HIV).b. Giardiasis, an infection of the upper small intestine that causes a diarrhealillness. Outbreaks can be difficult to control, especially in child care settingsc. Toxoplasmosis, transmitted to humans from cats and undercooked meat.When this systemic disease infects a pregnant woman, it can cause the death ofthe fetus.d. Pneumocystis carinii pneumonia or PCP, which is often fatal, especially inpeople with compromised immune systems such as those infected with HIV.3. Fungi are nonmotile, filamentous organisms that cause diseases that can be verydifficult to treat. Some examples important to public health are:a. Histoplasmosis, transmitted by inhaling dust from soil that contains birddroppings. The severity varies widely, with the lungs the most common site ofinfection.b. Candidiasis, transmitted by contact with human patients and carriers. Thisfungus causes lesions on the skin or mucous membranes, including “thrush” andvulvovaginitis. Symptoms can be severe in immunocompromised people.4. Bacteria are single-celled organisms that lack a nucleus. They are responsible for awide range of human diseases, including:a. Tuberculosis, a chronic lung disease that is a major cause of disability anddeath in many parts of the world.b. Staphylococcal disease, which can affect almost every organ system.Severity ranges from a single pustule of impetigo, through pneumonia, arthritis,endocarditis, etc., to sepsis and death.c. Chlamydia and gonorrhea, the most widespread sexually transmitteddiseases.d. Tetanus and diphtheria, two diseases that were once major public healthproblems but are now well controlled through immunization.d. Other vaccine-preventable diseases caused by bacteria are: Pertussis Haemophilus influenzae type b (Hib) Pneumococcal disease.2
5. Rickettsia are a genus of bacteria usually found in the cells of lice, ticks, fleas andmites. They are smaller than most bacteria and share some characteristics of viruses.Diseases cause by rickettsia include:a. Rocky Mountain Spotted Fever, a tick-borne systemic disease that can behard to diagnose and that leads to death in 3-5% of US cases.b. Typhus, a louse-borne rash illness with a high case-fatality rate that hasoccurred historically in poor living conditions brought on by war and famine.6. Viruses are very small, consisting of an RNA or DNA core and an outer coat ofprotein. They can reproduce and grow only inside of living cells. Many viral illnessesare significant to public health, including:a. Influenza, a respiratory illness that contributes to development of pneumoniaand occurs in annual epidemics during the winter monthsb. HIV (human immunodeficiency virus), that causes Acquired ImmunodeficiencySyndrome (AIDS). This severe, life-threatening pandemic disease has spreadworldwide within the past 20-30 years.c. Rabies, that is spread to humans from animal bites or scratches. Rabies isalmost always fatal in humans but is preventable by a vaccine.d. Measles, mumps, rubella, and poliomyelitis are all well controlled in the USthrough immunization.7. Prions are infectious agents that do not have any genes. They seem to consist of aprotein with an aberrant structure, which somehow replicates in animal or human tissue.Prions cause severe damage to the brain. Diseases associated with prions include:a. CWD, chronic wasting disease of mule, deer and elk;b. BSE, bovine spongiform encephalopathy in cows; andc. CJD, Creutzfeld-Jacob disease in humans.[B. ReservoirsThe next essential link in the chain of infection is the reservoir, the usual habitat inwhich the agent lives and multiplies. Depending upon the agent, the reservoir may be: humans, animals, and/or environmentWhen working with any disease agent, it is important to learn about its usualreservoir(s).1. Human ReservoirsThere are two types of human reservoirs, acute clinical cases and carriers.a. Acute clinical cases are people who are infected with the disease agent andbecome ill. Because they are ill, their contacts and activities may be limited.3
They are also more likely to be diagnosed and treated than carriersare.b. Carriers, on the other hand, are people who harbor infectious agents but arenot ill. Carriers may present more risk for disease transmission than acuteclinical cases, because their contacts are unaware of their infection,and their activities are not restricted by illness. Depending on the disease, any of the following types of carriers maybe important:Incubatory carriersInapparent infections (also called subclinical cases)Convalescent carriersChronic carriersIncubatory carriers are people who are going to become ill, but begintransmitting their infection before their symptoms start. Examples:measles: a person infected with measles begins to shed the virus in nasaland throat secretions a day or two before any cold symptoms or rash arenoticeable. Many other diseases also have an incubatory carrier phase.Most notably, HIV infection may be present for years before the persondevelops any symptoms.Inapparent infections: People with inapparent infections never develop anillness, but are able to transmit their infection to others. With somediseases, inapparent infections are more common than acute clinicalcases. Example: Of every 100 individuals infected with the poliomyelitisvirus, only one becomes paralyzed. Four others will have a mild illnesswith fever, malaise, headache, nausea and vomiting. But 95 out of the100 will have no symptoms at all, although they pass the virus in theirfeces.Sometimes the likelihood of an inapparent infection depends on anotherepidemiologic factor, such as age. Hepatitis A is a good example of this.Over 50% of adults infected with this virus develop symptoms. However,among children under 5, there may be 10 inapparent infections for everychild who develops jaundice. So children are very effective spreaders ofthe hepatitis A virus, which is passed in the feces regardless of thepresence of symptoms.Subclinical infections: With some diseases, such as meningococcalmeningitis, the number of subclinical cases may be quite high before asingle clinical case appears. On some military bases where outbreakshave occurred, the carrier rate has been documented at 50% or more.4
Convalescent carriers are people who continue to be infectious during andeven after their recovery from illness. This happens with many diseases.Example: Salmonella patients may excrete the bacteria in feces forseveral weeks, and rarely even for a year or more. This is most commonin infants and young children. Treatment with inappropriate antibioticsmay prolong the convalescent carrier phase.Chronic carriers are people who continue to harbor infections for a year orlonger after their recovery. Example: the chronic carrier state is notuncommon following hepatitis B infection, whether or not the personbecame ill, and may be lifelong. The risk of developing chronic hepatitis Bdepends on the person’s age at infection. About 90% of infants infected atbirth become chronic carriers of the disease, compared with only 1-10%infected after age 5. That is why it is so important to give hepatitis Bvaccine to newborns.2. Animal ReservoirsAnimal reservoirs of infectious agents can be described in the same way as humanreservoirs. They may be acute clinical cases, or carriers.Depending upon the disease, different carrier phases may be important in transmission.3. Environmental ReservoirsPlants, soil and water may serve as the reservoir of infection for a variety of diseases. Most fungal agents (mycoses) live and multiply in the soil.Examples:The organism that causes histoplasmosis lives in soil with high organiccontent and undisturbed bird droppings.The agents that cause tetanus, anthrax and botulism are widely distributedin soil.The agent of Legionnaire’s Disease lives in water, including hot waterheaters.C. Portal of ExitThe next link in the chain of disease transmission is the portal of exit, the route bywhich the disease agent may escape from the human or animal reservoir. Whilemany disease agents have only one portal of exit, others may leave by various portals.The portals most commonly associated with human and animal diseases are: Respiratory Genitourinary Alimentary SkinSuperficial lesions5
PercutaneousTransplacental1. Respiratory: This is the route of many disease agents that cause respiratoryillnesses such as the common cold, influenza, and tuberculosis. It is also the routeused by many childhood vaccine-preventable diseases, including measles, mumps,rubella, pertussis, Haemophilus influenzae type b (Hib), and pneumococcal disease.This is the most important portal and the most difficult to control.2. Genitourinary: This portal of exit is the route of sexually transmitted diseases,including syphilis, gonorrhea, chlamydia, and HIV. Schistosomiasis, a parasitic disease,and leptospirosis, a bacterial infection, are both spread through urine released into theenvironment.3. Alimentary: The alimentary portal of exit may be the mouth, as in rabies and otherdiseases transmitted by bites. More commonly, disease agents are spread by the otherend of the intestinal tract. These are referred to as enteric diseases. In general, entericdiseases may be controlled through good hygiene, proper food preparation and sanitarysewage disposal. Examples include: Hepatitis A Salmonella, including typhoid Shigella Cholera Giardia Campylobacter4. Skin: Skin may serve as a portal of exit through superficial lesions or throughpercutaneous penetration. Superficial skin lesions that produce infectious discharges are found insmallpox, varicella (chickenpox), syphilis, chancroid, and impetigo. Percutaneous exit occurs through mosquito bites (malaria, West Nile virus) orthrough the use of needles (hepatitis B and C, HIV).5. Transplacental: This portal of exit from mother to fetus is important in thetransmission of rubella, HIV, syphilis, and cytomegalovirus (the most common infectiouscause of developmental disabilities). It is, fortunately, not a factor for most diseases.D. Mode of TransmissionA mode of transmission is necessary to bridge the gap between the portal of exit fromthe reservoir and the portal of entry into the host. The two basic modes are direct andindirect.1. Direct transmission occurs more or less immediately. Many diseases aretransmitted by direct contact with the human, animal or environmental reservoir. Prime6
examples are sexually transmitted diseases and enteric diseases such as shigella,giardia and campylobacter. Contact with soil may lead to mycotic (fungal) diseases.Droplet spread is also considered direct transmission. Infectious aerosols produced bycoughing or sneezing can transmit infection directly to susceptible people up to threefeet away. Many respiratory diseases are spread this way.2. Indirect transmission may occur through animate or inanimate mechanisms. Animate mechanisms involve vectors. Flies may transmit infectious agents suchas shigella in a purely mechanical way, by walking on feces and then on food.Mosquitoes, ticks or fleas may serve as reservoirs for the growth andmultiplication of agents, for example in malaria or Lyme disease. Inanimate mechanisms: When disease agents are spread by environmentalvehicles or by air, this is referred to as indirect transmission by inanimatemechanisms. Anything may be a vehicle, including objects, food, water, milk, orbiological products.o Food is a common vehicle for salmonella infectionso Water is the usual vehicle in cholera outbreakso Surgical instruments and implanted medical devices may be the vehiclesof staphylococcal infectionsIndirect, airborne transmission is important in some respiratory diseases. Thisoccurs when very tiny particles of respiratory material become suspended in theair (called aerosols). Such particles may remain suspended and stay infectiousfor varying periods of time. They are particularly dangerous because their size (1to 5 microns) allows them to be drawn deep into the lungs and retained.Tuberculosis is spread this way, as is measles in certain settings such asdoctors’ offices. Air may also spread particles of various sizes fromcontaminated soil, or from objects such as clothing and floors.E. Portals of EntryThe portal of entry into the host is usually the same as the portal of exit from thereservoir.In some diseases, however, the exit and entry portals may differ. Example:staphylococcal bacteria may escape from one person’s respiratory tract to infectanother person’s skin lesion. If that person is a foodhandler, the staphylococcalbacteria may escape from the infected skin lesion, contaminate food where it canincubate, and cause “food poisoning” in people eating the food.F. Susceptible Host7
The last essential component in the chain of infection is the susceptible host.Susceptibility is affected by: Genetic factors General resistance factors Specific acquired immunity1. Genetic factors The role of genetic factors in susceptibility to infectious diseases isnot yet well understood. Genes do seem to play a role in the progression of HIVdisease, and perhaps in individuals’ susceptibility to meningococcal meningitis.2. General resistance factors include many body functions that we take for granted.Intact skin and mucous membranes help us resist disease. So do the gastric acid in ourstomachs, the cilia in our respiratory tracts, and the cough reflex.3. Specific acquired immunity is the greatest influence on host susceptibility. Thisimmunity is specific to a particular disease agent, and it may be acquired naturally orartificially. Natural immunity may be acquired by experiencing an infection, which iscalled “active natural immunity.
A. EPIDEMIOLOGY is derived from three Greek root words: epi - on, upon demos - people logy - study Epidemiology is, thus, the study of what is upon the people. In modern terms, it is the science of the distribution of disease and its determinants (causes). Epidemiology is also a process that uses the facts at hand as clues to point to new
Infectious Disease epidemiology BMTRY 713 (Lecture 15) Midterm Reviews and Recaps March 7, 2017 Selassie AW (DPHS) 1 Infectious Disease Epidemiology BMTRY 713 (A. Selassie, DrPH) Learning Objectives 1. Summary Review of the first 14 class lectures before midterm 2. Answer questions about exam format 3. Provide a sample test March 7, 2017 Lecture 15
An infectious disease is a clinically evident disease resulting from the presence of pathogenic microbial agents.1 Infectious diseases represent a major threat; millions die as a result of an infectious disease every year.2 Infectious disease can be transmitted through several methods, including physical contact with infected
Pediatric Infectious Disease 2018 Annual Report Division Introduction Under the direction of Jeffrey Kahn, M.D., Ph.D., the Division of Pediatric Infectious Disease directs and manages two active in-patient infectious disease consultation services; one dedicated to general infectious diseases and the other dedicated to
Introduction to Epidemiology Epidemiology yIs the process to study the distribution and determinants of disease frequency yIs a discipline which approaches problems systematically and quantitatively yIs the basic science of public health The Public Health Cycle Measure/Evaluate Epidemiology Analyze Epidemiology Communicate Intervene Epidemiology
form the core of traditional psychosocial epidemiology derive from those of infections disease epidemiology. That field seeks to describe the relationships among and between a population, its environment, and some disease agent, such as influenza virus. Often successful work in infectious disease epidemiology
Epidemiology and Emerging Infections Reportable Infectious Diseases Reference Manual September 16, 2019 CONNECTICUT DEPARTMENT OF PUBLIC HEALTH – INFECTIOUS DISEASES SECTION 410 Capitol Ave., MS# 11FDS, Hartford, CT 06134 Phone: 860-509-7995 FAX: 860-509-7910 2019 ROUTINE REPORTABLE INFECTIOUS DISEASE FOLLOW-UP
Principles of epidemiology in public health practice, third edition. An introduction to applied epidemiology and biostatistics. Lesson six: investigating an outbreak. . In: Gertsman BB, ed. Epidemiology kept simple: an introduction to traditional and modern epidemiology. 2nd ed. Hoboken, NJ: Wiley-Liss, Inc.; 2003:351-64. 3. Brownson RC .
accounting requirements for preparation of consolidated financial statements. IFRS 10 deals with the principles that should be applied to a business combination (including the elimination of intragroup transactions, consolidation procedures, etc.) from the date of acquisition until date of loss of control. OBJECTIVES/OUTCOMES After you have studied this learning unit, you should be able to .
